Some sources for purchasing retired Department 56 pieces include Replacements.com and CityLightsCollectibles.com as of 2016. As they are retired, the stock and availability of these items are constantly changing.
Replacements.com offers more than 30 different styles of retired Department 56 pieces. Some of the pieces come in the original boxes and others don't, but each is clearly marked. Underneath the photo of each piece is the number of available stock.
CityLightsCollectibles.com sells both current and retired Department 56 pieces. Customers can filter out the new items. There are more than 200 retired items, and each features a photo and the manufacturer number. In the top right hand corner, there is a red marker with the word "Retired" clearly marked.